Automatic timers for operating toggle switches to turn lights on and off are known. For example, a continuously cycling automatic timer attachment for a wall mounted toggle switch is disclosed in the Trock U.S. Pat. No. 3,179,758. A Schneidinger U.S. Pat. No. 3,985,982 discloses a light switch actuating device which is mounted onto a wall space and actuates a toggle switch in a room and includes a single override switch.
Electronic wall switches are also well known. For example, the Martin U.S. Pat. No. 4,194,182 discloses an electrical switch controllable alternately by an internal timer and a digital information from a remote source. As disclosed therein, an electrical timer is used to turn a light on and off. An electronic wall switch is also disclosed in a Nilssen U.S. Pat. No. 4,835,413. As disclosed therein, a compact lightweight electronic actuator which is mounted on the outside of an ordinary wall switch and operable to permit touch-operated time automatic actuation of the wall switch actuating lever.
Notwithstanding the above, it is now believed that there may be a large commercial market for an improved mechanical timer switch in accordance with the present invention. It is believed that there is a commercial market because the switches in accordance with the present invention can be easily and safely installed by a homeowner at a relatively low cost. Further, such switch assemblies incorporate a mechanical as opposed to an electrical timer to turn the lights on and off.
Further advantages of the mechanical timer switch assemblies in accordance with the present invention reside in its compact assembly which is incorporated within a conventional electrical receptacle box with only a relatively small rotatable knob, one or two push button switches and a locking switch on the outside of the receptacle box cover plate. The rotatable knob and push button switch are on the outside of the cover plate, but do not extend outwardly by much more than an electrical toggle switch. For comparison, the aforementioned prior art patents with the exception of Martin, U.S. Pat. No. 4,194,182 include mechanisms on the outside of the cover plate. Also, each of the aforementioned patents incorporate a toggle lever which has been eliminated in the presently disclosed assembly.
An additional advantage of the present invention resides in the use of a mechanical switch to automatically turn off a light after a pre-selected time. Further, a simple three way switch circuit may be used to connect the rotary timer switch and a push button switch or other type of switch in a manner that minimizes the need for an electrician to install the switch. In addition, the mechanical timer switch assemblies in accordance with the present invention can be manufactured at a relatively low cost, are durable and readily installed in a conventional receptacle box and eliminates the need for a mechanical mechanism to actuate a conventional toggle switch. These and other advantages will be readily apparent from the detailed description of the invention that follows.